From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754712AbZKSRWe (ORCPT ); Thu, 19 Nov 2009 12:22:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754552AbZKSRW0 (ORCPT ); Thu, 19 Nov 2009 12:22:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:18763 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753723AbZKSRWX (ORCPT ); Thu, 19 Nov 2009 12:22:23 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells Subject: [PATCH 20/28] FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure To: linux-cachefs@redhat.com, nfsv4@linux-nfs.org, linux-kernel@vger.kernel.org Cc: dhowells@redhat.com, steved@redhat.com Date: Thu, 19 Nov 2009 17:22:16 +0000 Message-ID: <20091119172216.1679.81427.stgit@warthog.procyon.org.uk> In-Reply-To: <20091119172033.1679.87046.stgit@warthog.procyon.org.uk> References: <20091119172033.1679.87046.stgit@warthog.procyon.org.uk> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We must make sure that FSCACHE_COOKIE_LOOKING_UP is cleared on lookup failure (if an object reaches the LC_DYING state), and we should clear it before clearing FSCACHE_COOKIE_CREATING. If this doesn't happen then fscache_wait_for_deferred_lookup() may hold allocation and retrieval operations indefinitely until they're interrupted by signals - which in turn pins the dying object until they go away. Signed-off-by: David Howells --- fs/fscache/object.c | 17 ++++++++++++----- 1 files changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 1a1afa8..74bc562 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -105,6 +105,7 @@ static inline void fscache_done_parent_op(struct fscache_object *object) static void fscache_object_state_machine(struct fscache_object *object) { enum fscache_object_state new_state; + struct fscache_cookie *cookie; ASSERT(object != NULL); @@ -158,11 +159,17 @@ static void fscache_object_state_machine(struct fscache_object *object) spin_lock(&object->lock); object->state = FSCACHE_OBJECT_DYING; - if (object->cookie && - test_and_clear_bit(FSCACHE_COOKIE_CREATING, - &object->cookie->flags)) - wake_up_bit(&object->cookie->flags, - FSCACHE_COOKIE_CREATING); + cookie = object->cookie; + if (cookie) { + if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, + &cookie->flags)) + wake_up_bit(&cookie->flags, + FSCACHE_COOKIE_LOOKING_UP); + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, + &cookie->flags)) + wake_up_bit(&cookie->flags, + FSCACHE_COOKIE_CREATING); + } spin_unlock(&object->lock); fscache_done_parent_op(object);